Yeah... I remember reading that... this is the part that made me pause a bit:
Rotate the top of the pump back toward the head until you feel the bolt touch the pump piston.
Might have to do an experiment or two... I wondered if you could detect the pump piston just touching the bolt, vs. mashing it down.... the thinking being there's probably a fair number of thousandths of an inch between "touchdown" and "mashdown" ??
Another thought I had was a slight variation on the beautiful tool tawney built to hold the plunger et. al. in place while changing the high pressure O-ring in situ.

It might be possible to mark excursions at 0, 0.95mm, 1.00mm, and 1.05mm, and so on on the outside of the plunger. Rotate the engine back until the plunger stops moving and then screw the tool in or out until it hits the 0 hash mark. Rotate back to TDC and then rotate the pump till you hit the hash mark on the plunger you're after.
Having a spring touch the plunger seems a bit more gentle than the hard stop of a bolt, too ?
I personally hate that damn dial indicator some days.. pulling various bits off to make room for it, having it bind and loosen... all we really need is something that threads into an 8x1 hole and reads one distance.
Paging tawney !!!
(sorry OP, we're getting a bit off topic, but we just might save ya 50 bucks in the end !)